Photovoltaic-ferroelectric data recorder

Abstract

A data recording and read-out apparatus and method in which a ferroelectriceramic substrate is remanently polarized to store information. Upon being illuminated, the substrate produces a photovoltaic voltage, which is detected to effect read-out. A disk of ferroelectric ceramic material to which information is entered by spiral tracking, either in a single track or in multiple tracks. A self-scanning data record comprised of a plurality of ferroelectric ceramic cells which are remanently polarized, and which are read out by a register.

What is claimed is: 
     
       1. A photovoltaic information storage and read-out apparatus comprising, a substrate of ferroelectric ceramic material,   means for applying an electrical signal having a predetermined polarity across at least a region of said substrate to effect a remanent ferroelectric polarization in said region representative of said information to be stored,   means for illuminating said at least a region of said substrate with a source of radiation, whereby a photovoltaic voltage is produced at said region having a polarity dependent on the polarity of said polarizing electrical signal, and,   means for detecting the polarity of said photovoltaic voltage, whereby the stored information is retrieved.   
     
     
       2. A photovoltaic storage and read-out apparatus comprising, a substrate of ferroelectric ceramic material,   means for applying an electrical signal having a predetermined magnitude across at least a region of said substrate to effect a remanent ferroelectric polarization in said region representative of said information to be stored,   means for illuminating said at least a region of said substrate with a source of radiation, whereby a photovoltaic voltage is produced in said region having a magnitude dependent on the magnitude of said polarizing electrical signal, and,   means for detecting the magnitude of said photovoltaic voltage, whereby the stored information is retrieved.   
     
     
       3. The apparatus of claim 1 wherein said substrate is disk-shaped, is deposited on a conducting surface, said means for applying an electrical signal comprises means for applying a signal to said substrate in a spiral tracking pattern. 
     
     
       4. The apparatus of claim 3 wherein said disk has an exposed surface and said means for illuminating comprises means for illuminating the entire exposed surface simultaneously. 
     
     
       5. The apparatus of claim 4 wherein said means for applying an electrical signal comprises means for applying a plurality of electrical signals in concentric spiral tracks. 
     
     
       6. The apparatus of claim 5, wherein said means for detecting comprises means for detecting a plurality of photovoltaic voltages in concentric spiral tracks. 
     
     
       7. The apparatus of claim 1 wherein said substrate comprises at least a part of a tape. 
     
     
       8. The apparatus of claim 1 wherein said substrate is deposited on a drum. 
     
     
       9. An information storage and read-out apparatus comprising, a plurality of cells of ferroelectric ceramic material, each cell being remanently polarized,   means for illuminating said cells, each cell thus producing a photovoltaic voltage,   means for parallel-transferring the voltage produced by each cell to the stages of a register means, and   means for serially reading out the contents of said register means.   
     
     
       10. The apparatus of claim 9 wherein said register means comprises charge control device register means. 
     
     
       11. The apparatus of claim 9 wherein said register means comprises shift register means. 
     
     
       12. An apparatus of claim 9 wherein said plurality of cells comprises a plurality of rows and columns of cells, and said means for illuminating comprises means for illuminating a selected row at a time. 
     
     
       13. A method of storing information comprising, providing a substrate of ferroelectric ceramic material,   applying an electrical signal having a predetermined polarity across at least a region of said substrate to effect a remanent ferroelectric polarization in said region representative of said information to be stored,   illuminating said at least a region of said substrate with a source of radiation whereby a photovoltaic voltage is produced at said region having a polarity dependent on the polarity of said electrical signal, and   detecting the polarity of said photovoltaic voltage, whereby said stored information is retrieved.   
     
     
       14. An information storage and read-out apparatus comprising, shift register means,   a plurality of cells of ferroelectric ceramic material,   a transfer switch means connected between each stage of said shift register means and a said cell   voltage source means, and   switch means connected between said voltage source means and said transfer switch means for applying a voltage from said source to said transfer switch means for transfer to said cells.